Ignition unit



Jan. l, 1946. M. o. MARSH IGNITION UNIT Filed Jan. 1, 194e Inventor:Myfle O. Marsh, by WM His Attorney.

Patented Jan. 1, 1946 IGNITION UNIT Myrle 0. Marsh, Fort Wayne,

General Electric Company,

New York Ind., assigner to a corporation oi' Appllcaton January 1, 1943,Serial No. 470,980

12 Claims.

My invention relates to ignition units and particularly to a highfrequency electric spark discharge unit such as may be used inconnection with internal combustion engines.

An object of my invention is to provide an im proved ignition unit oithe high frequency type.

Another object of my invention is to provide an improved ignition unitprovided with an oscillation discharge circuit for supplying a highfrequency current to discharge electrodes thereof.

Further objects and advantages of my invention will become apparent andmy invention will be better understood from the following descriptionreferring to the accompanying drawing, and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming part of this specification.

In the drawing, Fig. l is a sectional view through an ignition unitembodying my invention wherein the unit includes an improved form ofoscillation transformer and discharge electrodes; Fig. 2 is a sectionalview showing a modification of the arrangement in Fig. 1 wherein theunit includes the features of Fig. 1 and in addition a compactoscillation circuit formed by a capacitor, a quenched spark gap device,and an oscillation transformer connected to discharge electrodes; andFig` 3 is a further modication of the arrangement shown in Fig. 2wherein a single high dielectric constant insulating material is used toinsulate the primary and secondary windings from each other and from thebarrel of the unit.

Referring to the drawing, I have shown in Fig. 1 an embodiment of myinvention wherein an ignition unit is provided with a barrel or shelliii which is adapted to be secured in a threaded opening in an enginecylinder bloei: by engagement therewith of a lower threaded portion iiof the barrel. A source of high frequency electric current is suppliedto the unit by a distributor lead conductor i2 arranged within a radioshielding armor i3 and insulated therefrom by an insulating covering il.The conductor i2 is secured to the ignition unitl in an insulatingterminal plug element i5 in which a terminal screw Iii is threaded intogood electrical contact with the end of the distributor conductor i2.This terminal plug I5 is held in position in the upper end of the barreli by securing a flange il of the plug i between the upper end of thecasing i0 and a flange IB formed on the end of the shielding armor i3.This assembly is retained in assembled relationship by a nut I9 whichthreadedly engages the upper end 29 of the barrel ill and is providedwith an inturned flange 2| which engages the outer surface of the ilangeI8 and biases the flange IB toward the end of the barrel IB. Theterminal screw i8 forms an electrical contact with spring lingers 22 ofa terminal cap 23 provided with a threaded retaining end portion 2|molded within a core member 25 of high dielectric constent and fusingpoint insulating material, such as porcelain or other suitable material.The high frequency current supplied to the ignition unit by thedistributor conductor i2 is adapted to be supplied at a relatively lowvoltage to a primary winding 26 of an oscillation transformer which isconnected at one end 21 to the terminal 24 and at the other end 23thereof to the barrel Ill through a sleeve 29 of electrically conductivematerial. The oscillation transformer is provided with a secondarywinding 30 which is arranged about the upper portion of the insulatingmember 25 which forms a SuDDOrting core for the secondary winding 39extending substantially the full length thereof and is insulated fromthe transformer primary winding 26 by an insulating sleeve eiement 3i.One terminal 32 of the transformer secondary winding 30 is connected tothe terminal element 24 and to the adjacent end 21 ci the transformerprimary winding, and the other end 33 of the transformer secondarywinding extends through an opening 34 in the insulating core 25 into acentral opening 35 formed in the lower end of the core element 25. Theend 33 of the transformer secondary winding is electrically connected toa central spark discharge electrode 36 which is mounted in the opening35 in the insulating core element 25 and is held in position therein bya pin 3l which extends through the electrode 33 and. into pockets formedin the insulating core member 25. An insulating plug 38 is arranged overthe end of the pin 3l in the core member to prevent electricaldischarges between the pin 3l and the sheii Iii. The insulating coremember l25 is secured in position within the shell iii by a shoulder 39formed thereon arranged in engagement with a gasket 4D pressed betweenthe shoulder 39 and a flange AI formed on the barrel l0. Provision ismade for the desired expansion due to the variations in temperature ofthe ignition unit by the arrangement of the sleeve 29 about the shoulderportion 39 of the insulating core member 25 and by the gasket 4i whichvaries in dimension under the different heat conditions to provide foran'y relative difference in expansion and contraction between the barrelIIJ and the core member 25. The shoulder 39 of the core member 25 isheld in the above-mentioned position by a ring 42 arranged in the lowerend of the barrel i in engagement with the lower edge of the shoulderportion 39 between this lower edge and a set of discharge electrodes 43.A ange or lip 44 formed on the lower end of the barrel I0 is turned into hold these elements in assembled relationship. This arrangementprovides a spark discharge gap between the central electrode 35 and theelectrodes 43 which is supplied with a high frequency current at arelatively high voltage by the transformer secondary winding andminimizes the possibility of electrical losses and discharges betweenthe source of high-voltage high-frequency current and the sparkdischarge electrodes.

In Fig. 2, I have shown a modification of the arrangement shown in Fig.1 wherein the ignition unit includes a self-contained oscillatorycircuit. As in the arrangement shown in Fig. 1, the ignition unitincludes a shell Il! in which an oscillation transformer having aprimary winding 28 and a secondary winding insulated from each other byan insulating sleeve 3| are mounted about a core of insulating material25 to supply high-voltage high-frequency current to a central ignitionelectrode 35. This central electrode is supported by the insulating core25 to provide a spark discharge gap between it and cooperating sparkdischarge electrodes 43 supported in electrica] contact with the lowerend il of the shell i5 by -an inturned lip portion 44. One terminal 33of the transformer secondary winding 30 is electrically connected to thecentral discharge electrode 36, and the other terminal 32 iselectrically connected to a terminal of the primary winding 21 and to aterminal screw 45 about which the upper end of the insulating core 25 ismolded. This terminal screw is adapted to be electrically connecteddirectly to one terminal of a quenched spark gap device so as to reducethe variations in capacitance and inductance due to the arrangement ofthe distribution leads or connections between the parts of theoscillatory circuit and the oscillation transformer. 'I'his connectionis formed by a non-inductive linger spring 48 arranged in contact withthe head of the screw and mechanically and electrically connected by arivet 41 to a terminal cup 48 of a quenched spark gap device. Thisquenched spark gap device is provided with a second terminal cup 49arranged on the opposite side of the device from the terminal cup 48 toprovide an enclosing housing or casing for the quenched spark gap. Thetwo terminal cups 48 and 49 are secured together and insulated from eachother by an annular seal 58 of suitable material, such as glass, whichis rigidly secured to the open ends of the cups by being moldedthereabout. This quenched spark gap is formed between a pair of similarspark discharge buttons 5I and 52 provided with sparking faces 53 and 54of suitable material, such as cadmium, and are provided with stemportions 55 and 55 which extend through openings in supporting andspacing members 51 and 58 and are secured thereto by upset rivet headportions 59 and 58. The spacing members 51 and 58 are held inpredetermined spaced apart relationship by a spacing ring 5i formed of asuitable insulating material, such' as pressed mica, arranged betweenthe adjacent inner edges thereof and firmly biased towards each otherand against the sides of the ring 5I by pressure exerted on the outeredges thereof by the terminal cups 48 and 43 through locating rings 52and 53. 'I'he spacing members 51 and 58 are held in their centeredpositions by a locating ring 84 of suitable insulating material, such asa h'eat hardenable resin, arranged about the outer cylindrical sur facesof the spacing elements 51 and 59. An insulating sleeve 55 extendsbetween the outer surface oi' the quenched spark gap device and theinner portion of the barrel i0 to insure against electrical dischargestherebetween. The termi nal cup 49 of the quenched spark gap device iselectrically connected to a distributor lead 55 through a terminal screw81 which contacts the terminal cup 59 and is held in position in aterminal element 58 electrically connected to one terminal of acapacitor 89. The capacitor 59 is electrically connected across theseries circuit formed by the spark gap device and the primary winding 28of the oscillation transformer. and one side thereof is electricallyconnected to the distributor lead 55 by the terminal 58 and the otherside thereof is electrically connected to an enclosing electricallyconductive casing 1li which forms an upper closure for the shell III.The casing 1li is secured in position by a cap nut 1I provided with aninturned flange 12 which extends over an outturned flange 13 formed onthe lower end of the casing 1li to secure the casing flange 13 betweenthe nut flange 12 and the upper edge of the barrel I8. The nut is drawnup tightly by threaded engagement of the lower threaded portion 14thereof with a complementary threaded portion on the upper end of thebarrel Iii. With this construction, the lengths of the connectingportions of the oscillation discharge circuit are reduced to a minimumand these connections are all formed by relatively non-inductiveelements so that the inductances and capacitances of the oscillationcircuit are essentially provided by the units designed for this purpose.With such a construction, a standard 40 ignition unit having a fixedoscillation circuit can be provided for all of the cylinders and for allof the ignition units of each cylinder and the different lengths of thedistributor leads have a minimum effect on the oscillation of thecircuit.

In Fig. 3, I have shown another embodiment of my invention in which aself -contained oscillation discharge circuit is provided for theignition unit somewhat similar to that shown in Fig. 2. In thisconstruction, the oscillation circuit includes a capacitor 59 arrangedwithin the casing 10 and one side thereof is electrically connected tothe casing 10 by a resilient non-inductive finger spring 15 arranged tobias the condenser 59 away from the upper end of the casing 1li. Theother side of the condenser 59 is connected to the distributor lead 86by the terminal element 58 and to the terminal cup 49 of the quenchedspark gap device 'by the terminal screw 51, as in the construction shownin Fig. 2'. In this arrangement, the spark discharge device is madesubstantially the same as that in Fig. 2, and is formed with two similarterminal cups 48 and 49 which are sealed and held together by an annularglass element 55. In order to minimize the possibility of electricaldischarge between different parts of the oscillation transformer andbetween parts of the oscillation transformer and the barrel i0, theoscillation transformer elements are formed and enclosed within aninsulating member 16 of suitable insulating material, such as a leadborosilicate type glass which has a coefficient of thermal expansionsubstantially the same as that of the barrel I0. The barrel i0 and thewindings of the oscillation transformer are formed of a material, suchas nickel-iron, with substantially the same assainwinding 11 formed of acon having s few turns with one terminal 1l thereof electricallyconnected to a terminal I8 electrically connected to the terminal cup I8of the quenched spark gap device, and provided with a terminal I8electrically connected to the barrel Hl. A secondary transformer windingIl formed of a large number of turns is arranged within the primarywinding 11 with one terminal B2 thereof electrically con' nected to theterminal 1! of the spark discharge device and the other terminal 83thereof electrically connected to a central spark discharge electrode84. The transformer primary and secondary windings I1 and BI and thedischarge electrode B4 are supported in their desired relationship toeach other by having parts thereof molded in theinsuleting element 18.Thus, the insulating element l5 provides a single high dielectricconstant high temperature fusing point insulating material between allof the parts of the oscillation transformer and the barrel Ill andminimizes the possibility of discharges therebetween. As in thearrangement shown in the other figures, a plurality of dischargeelectrodes 85 is connected to the lower end of the barrel lil by aninturned lip 8S and held in spaced apart relationship relative to thecentral electrode all to provide the desired spark discharge gap betweenthese electrodes. 'Ihe various elements of the ignition unit areresiliently held together within the barrel il) by the biasing action ofthe contact finger spring I5 to minimize the transmission of destructiveforces and vibrations from the engine to the eiements forming the unit.In addition, it is desirable that the electrodes, the oscillationtransformer, and the quenched gap discharge device should be heldrigidly within the unit to provide the desired xed relationship betweenthe discharge electrodes 84 and 85 and to minimize the possibility ofbreaking the electrical connections between the various units. This isobtained by rigidly clamping together these units by the cap nut 'llwhich transmits a clamping pressure through the inturned nut flange 'l2to the casing nange 13 and a flange 81 formed on the outside of theinsulating sleeve 65. The insulating sleeve $5 is arranged with asurface which firmly engages the outer surface of the spark dischargeannular glass sealing element 50 and holds the spark discharge devicerigidly against the upper end of the glass insulating member 1B andthereby rigidly holds the oscillation transformer and the centralelectrode 84 in position within the barrel l0. With this construction, aminimum number of parts and breakdown circuits is provided as well as aself-contained oscillation circuit within the ignition unit withsubstantially non-inductive short electrical connections between thevarious parts of the circuit.

While I have illustrated and described particular embodiments of myinvention, modifications thereof will occur to those skilled in the art.desire it to be understood, therefore, that my invention is not to belimited to the particular arrangements disclosed, and I intend in theappended claims to cover all modifications which do not depart from thespirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. An ignition unit including a barrel, a spark electrode electricallyconnected to said barrel, a second spark electrode, an oscillationtransformer having a primary winding and a secondary wlnding arranged insaid barrel. means for electrically connecting one terminal of saidsecondary winding to said second spark electrodeI means for insulatingsaid primary winding from said secondary winding, a central core ofinsulating material about which said secondary winding is arrangedsubstantislly the full length of said secondary winding and in whichsaid second electrode is mounted insulated thereby from said barrel andarranged to provide a spark discharge gap with said first-mentionedelectrode, means for electrically connecting one terminal of saidprimary winding to said barrel, and means for providing an electricalconnection between the other terminal of said transformer primarywinding and a source of electrical power supply.

2. An ignition unit including a barrel, a spark electrode connected tosaid barrel, a second spark electrode, an oscillation transformer havinga primary winding and a secondary Winding arranged in said barrel, meansfor electrically connecting one terminal of said secondary winding tosaid second spark electrode, means for insulating said primary windingfrom said secondary winding, a central core of high dielectric constentand high temperature fusing point insulating material about which saidsecondary Winding is arranged substantially the full length of saidsecondary winding and in which said second electrode is mountedinsulated thereby from said barrel and arranged to provide a sparkdischarge gap with said first-mentioned electrode, means forelectrically connecting one terminal of said primary winding to saidbarrel, and means for providing an electrical connection between theother terminals of said transformer primary and secondary windings and asource of electrical power supply.

3. An ignition unit including a barrel, a spark electrode electricallyconnected to said barrel, a second spark electrode, an oscillationtransformer having a primary winding and a secondary winding arranged insaid barrel, means for electrically connecting one terminal of saidsecondary winding to said second spark electrode, means for insulatingsaid primary winding from said secondary winding, a central core ofinsulating materiai about which said secondary winding is arranged andin which said second electrode is mounted insulated thereby from saidbarrel and arranged to provide a spark discharge gap with saidfirst-mentioned electrode, means for electrically connecting oneterminal of said primary Winding to said barrel, and means including aquenched spark gap device arranged in and insulated from said barrelproviding an electrical connection between the other terminal of saidtransformer primary winding and a source of electrical power supply.

4. An ignition unit including a barre1 a spark electrode electricallyconnected to said barrel, a second spark electrode, a transformer havinga primary winding and a secondary winding arranged in said barrel, meansfor electrically connesting one terminal of said secondary winding tosaid second spark electrode, means for insulating said primary windingfrom said secondary winding, a central core of high dielectric constantinsulating material about which said secondary winding is arranged andin which said second electrode is mounted insulated thereby from saidbarrel and arranged to provide a spark discharge gap with saidfirst-mentioned electrode, means for electrically connecting oneterminal of said primary winding to said barrel, and means including aquenched spark gap device providing an electrical connection between theother terminal of said transformer primary winding and a source ofelectrical power supply.

5. An ignition unit including a barrel, a spark electrode electricallyconnected to said barrel, a second spark electrode, an oscillationtransformer having a primary Winding and a secondary winding arranged insaid barrel. means for electrically connecting one terminal of saidsecondary winding to said second spark electrode, means for insulatingsaid primary winding from said secondary winding, a central core of highdielectric constant high temperature fusing point insulating materialabout which said secondary winding is arranged and in which said secondelectrode is mounted insulated thereby from said barrel and arranged toprovide a. spark discharge gap with said first-mentioned electrode,means for electrically connecting one terminal of said primary windingto said barrel, and means including a quenched spark gap deviceproviding an electrical connection between the other terminal of saidtransformer primary and secondary windings and a source of electricalpower supply.

6. An ignition unit including a barrelI an oscillation discharge circuitarranged substantially within said barrel and including a spark elec-Ytrode electrically connected to said barrel, a second spark electrode, atransformer having a primary winding and a secondary winding arranged insaid barrel, means for electrically connecting one terminal of saidsecondary winding to said second spark electrode, means including asingle high dielectric constant insulating material element forinsulating said primary winding from said secondary winding arranged tosupport said windings and said second electrode in said barrel andinsulated therefrom and arranged to provide a spark discharge gapbetween said firstmentioned electrode and said second electrode, meansfor electrically connecting one terminal of said primary winding to saidbarrel, and means including a quenched spark gap device providing anelectrical connection between the other terminal of said transformerprimary winding and a source of electrical power supply.

7. An ignition unit including a barrel, an oscillation discharge circuitarranged substantially within said barrel and including a sparkelectrode electrically connected to said barrel, a second sparkelectrode, a transformer having a primary winding and a secondarywinding arranged in said barrel, means for electrically connecting oneterminal of said secondary winding to said second spark electrode, meansincluding a single high dielectric constant insulating material elementlor insulating said primary winding from said secondary winding arrangedto support said windings and said second spark electrode in said barreland insulated therefrom and arranged to provide a spark discharge gapbetween said first-mentioned electrode and said second electrode, meansfor electrically connecting one terminal of said primary winding to saidbarrel, and means for providing an electrical connection between theother terminal oi said transformer primary winding and a source ofelectrical power supply.

8. An ignition unit including a barrel, a spark electrode electricallyconnected to said barrel, a second spark electrode, a. transformerhaving a primary winding and a secondary winding arranged in saidbarrel, means for electrically connecting one terminal of said secondarywinding to said second spark electrode, means including a single highdielectric constant insulating material element for insulating saidprimary winding from said secondary winding forming a central boreforsaid secondary winding and in which said second electrode is mountedinsulated thereby from said barrel and arranged to provide a spark`discharge gap with said firstmentioned electrode, means forelectrically connecting one terminal of said primary winding to saidbarrel. means for providing an electrical connection between the otherterminal of said transformer primary winding and a source of electricalpower supply, and a capacitor in said barrel electrically connected tosaid barrel and to said source of electrical power supply.

9. An ignition unit including a barrel of electrically conductivematerial, a spark electrode electrically connected to said barrel, asecond spark electrode, an oscillation transformer having a primarywinding and a secondary winding arranged in said barrel, means forelectrically connecting one terminal of said secondary winding to saidsecond spark electrode, means including a single high temperature fusingpoint insulating material element for insulating said primary windingfrom said secondary winding arranged to support said windings and saidsecond electrode in said barrel and insulated therefrom and arranged toprovide a spark discharge gap between said mst-mentioned electrode andsaid second electrode, said barrel and said insulating material elementhaving substantially the same thermal coefficient of expansion, meansfor electrically connecting one terminal of said primary winding to saidbarrel, and means for providing an electrical connection between theother terminal of said transformer primary winding and a source ofelectrical power supply.

10. An ignition unit including a barrel, an oscillation dischargecircuit arranged substantially within said barrel and including a sparkelectrode electrically connected to said barrel, a second sparkelectrode, an oscillation transformer having a primary winding and asecondary winding arranged in said barrel, means for electricallyconnecting one terminal of said secondary winding to said second sparkelectrode, means for insulating said primary windlng from said secondarywinding, a central core of insulating material about which saidsecondary winding is arranged and in which said second electrode ismounted insulated thereby from said barrel and arranged to provide aspark discharge gap with said first-mentioned electrode, means forelectrically connecting one terminal of said primary winding to saidbarrel, means including a quenched spark gap device providing anelectrical connection between the other terminal of said transformerprimary winding and a source of electrical power supply, and a capacitorelectrically connected to said barrel and to said source of electricalpower supply across said circuit formed by said quenched spark gapdevice and said transformer primary winding,

ll. An ignition unit including a barrel, an oscillation dischargecircuit arranged substantially within said barrel and including a sparkelectrode electrically connected to said barrel, a second sparkelectrode, a transformer having a primary winding and a secondarywinding arranged in said barrel, means for electrically connecting oneterminal of said secondary winding to said second spark electrode. meansincluding a single high dielectric constant insulating material elementfor insulating said primary winding from said secondary winding arrangedto support said windings and said second electrode in said barrel andinsulated therefrom and arranged to provide a spark discharge gapbetween said rust-mentioned electrode and said second electrode, meansfor connecting one terminal of said primary winding to said barrel,means including a quenched spark gap device providing an electricalconnection between the other terminal oi said transformer primarywinding and a source of electrical power supply, and Va capacitorelectrically connected to said barrel and to said source of electricalpower supply across said circuit formed by said quenched spark gapdevice and said transformer primary winding.

12. An ignition unit including a barrel, an oscillation dischargecircuit arranged substantially within said barrel and including a sparkelectrode electrically connected to said barrel, a. second sparkelectrode, a transformer having a primary winding and a secondarywinding arranged in said barrel, means for electrically connecting oneterminal of said secondary winding to said second spark electrode. meansincluding a single high dielectric constant insulating material elementfor insulating said primary winding from said secondary winding forminga. central core for said secondary winding and in which said secondelectrode is mounted insulated thereby from said barrel and arranged toprovide a spark discharge gap with said iirst-mentioned electrode, meansfor connecting one terminal of said primary winding to said barrel,means including a quenched spark gap device providing an electricalconnection between the other terminal of said transformer primarywinding and a source of electrical power supply, and a capacitorelectrically connected to said barrel and to said source of electricalpower supply across said circuit formed by said quenched spark gapdevice and said transformer primary winding.

MYRLE O. MARSH.

DISCLAIMER 2,392,l7l.-Mfyrle 0. Marsh, Fort Wayne,

Company.

Ind. IGNITION Uma'. 1, 1946. Disclaimer ied Jan. 18,*1946, by theasslgnee,

Patent dated Jan. General Electric Hereby enters this disclaimer toclaims l, 2, 3, 4, 5, and l0 of said patent.

[Oficial Gazette February 26, 1.946.]

ing to said second spark electrode. means including a single highdielectric constant insulating material element for insulating saidprimary winding from said secondary winding arranged to support saidwindings and said second electrode in said barrel and insulatedtherefrom and arranged to provide a spark discharge gap between saidrust-mentioned electrode and said second electrode, means for connectingone terminal of said primary winding to said barrel, means including aquenched spark gap device providing an electrical connection between theother terminal oi said transformer primary winding and a source ofelectrical power supply, and Va capacitor electrically connected to saidbarrel and to said source of electrical power supply across said circuitformed by said quenched spark gap device and said transformer primarywinding.

12. An ignition unit including a barrel, an oscillation dischargecircuit arranged substantially within said barrel and including a sparkelectrode electrically connected to said barrel, a. second sparkelectrode, a transformer having a primary winding and a secondarywinding arranged in said barrel, means for electrically connecting oneterminal of said secondary winding to said second spark electrode. meansincluding a single high dielectric constant insulating material elementfor insulating said primary winding from said secondary winding forminga. central core for said secondary winding and in which said secondelectrode is mounted insulated thereby from said barrel and arranged toprovide a spark discharge gap with said iirst-mentioned electrode, meansfor connecting one terminal of said primary winding to said barrel,means including a quenched spark gap device providing an electricalconnection between the other terminal of said transformer primarywinding and a source of electrical power supply, and a capacitorelectrically connected to said barrel and to said source of electricalpower supply across said circuit formed by said quenched spark gapdevice and said transformer primary winding.

MYRLE O. MARSH.

DISCLAIMER 2,392,l7l.-Mfyrle 0. Marsh, Fort Wayne,

Company.

Ind. IGNITION Uma'. 1, 1946. Disclaimer ied Jan. 18,*1946, by theasslgnee,

Patent dated Jan. General Electric Hereby enters this disclaimer toclaims l, 2, 3, 4, 5, and l0 of said patent.

[Oficial Gazette February 26, 1.946.]

